Bridge tied load amplifier

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It's the first time i have posted in this forum cos i'm a new member.

I have a project of designing an amplifier using Bridge tied load model in order to make one which produce 500 W in a 8 -ohm speaker.

Unluckily, i don't have any background knowledge about BTL.

Does anyone have a sample schematic or any guides through which i could use to complete my desired design.


Please forgive me if i have posted in a wrong place.
 

djk

R.I.P
2001-02-04 4:23 am
USA
To further confuse the issue, how to run a LM3886 off ±100V and get 1KW at 2 ohms (see fig. 11)

http://www.national.com/an/AN/AN-446.pdf

This is called suspended supply operation. To drive 1KW at 2 ohms you would need ten LM3886 in parallel for A1, three pair of MJ21193/94 for Q1 and Q3, one pair of MJE15030/31 for Q2 and Q4, 35V zeners for D3 and D4.

This is a very advanced project and requires 0.1% resistors to set the gain around A1.
 
Hi romaprince,

A bridged load is driven by two amplifiers, with the "extra" amplifier driving the other side of the load, with an inverted copy of the signal.

Here is a national.com application note covering the basics of bridging and paralleling chipamps, just to familiarize you with the concepts and calculations involved:

http://www.national.com/an/AN/AN-1192.pdf

And below is a national.com appnote with basic examples related to adding power-booster amplifiers inside the feedback loops of opamps. Perhaps you could design something along the same lines as one of the examples (but with a higher-power discrete transistor booster stage), that might meet your requirements, when bridged. (Similarly, look at what djk suggested.)

http://www.national.com/an/AN/AN-272.pdf

However, it would probably be easier and maybe better to use something like the LME49810 with a discrete transistor power output stage. You should be able to get 500W into 8 Ohms even without bridging. See the application information near the end of the datasheet, at:

http://www.national.com/ds.cgi/LM/LME49810.pdf

The datasheet and application notes for the LM4702 will probably also be of interest:

http://www.national.com/ds.cgi/LM/LM4702.pdf
http://www.national.com/an/AN/AN-1490.pdf
http://www.national.com/an/AN/AN-1645.pdf

You might also find some useful ideas in AN18, at http://www.linear.com .

And you might also find some useful devices, datasheets, and application notes, at http://www.apexmicrotech.com .
 
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